Pluto isn't the only speck in the sky that's come into full, glorious focus over the last few months. NASA just released the first enhanced-color, high-resolution photo of Charon, the dwarf planet's largest moon. It offers an unprecedented look at Charon's surface, one that is both mesmerizing and informative. And yet it's just another small step in NASA's process of unraveling the mysterious history of the Pluto system.
Charon is half the diameter of Pluto, and is in what's known as a "tidal lock" with the dwarf planet. That means the two bodies always have the same face pointed at each other, much like the relationship of the Earth with our Moon. But that's where the similarities stop. Charon isn't just some dead rock with a bunch of dust and impact craters — it has vast canyons, mountains, and a colorful (if muted) surface that indicates the presence a wide variety of natural material. This is most noticeable with Charon's red north pole (informally named Mordor Macula), where New Horizons team members believe organic hydrocarbons may have somehow transferred over from Pluto.
One of the most striking features of Charon, though, is shown in great detail in the new images: the massive scarring across its midsection. This is a major system of canyons that stretches more than 1,000 miles (1,600 kilometers) across Charon's face, and perhaps to the other side. NASA says it's four times as long as the Grand Canyon, and twice as deep in some spots. It's the kind of geological formation that could only have happened on a very active world, which was the last thing NASA scientists expected of a moon this size and this far out in the Solar System.
Surprise has been a theme since New Horizons began its final approach of Pluto this summer. Few expected the dwarf planet to have vast mountains, exotic ice flows, a visible atmosphere, and a stockpile of methane. The same goes for Charon and its diverse landscape. There are certainly more surprises to come, as about 90 percent of the mission's data remains on the spacecraft.
- This high resolution scan of Charon’s surface was taken by the Long Range Reconnaissance Imager (LORRI) aboard the New Horizons spacecraft. It covers the entire width of Charon, which has a diameter of 754 miles (1,214 kilometers).
- NASA took the new color image of Charon and composited it next to a recent, false-color image of Pluto to show the relative size of each world. Charon is roughly half the size of Pluto, making it the largest satellite relative to its planet in our Solar System.
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